Circuit interrupters with improved snap acting operating mechanism



1966 A. BACHMAN 3,287,514

CIRCUIT INTERRUPTERS WITH IMPROVED SNAP ACTING OPERATING MECHANISM Filed Sept. 4, 1964 3 Sheets-Sheet 1 FIGJ ATTORNEY A. BACHMAN CIRCUIT INTERRUPTERS WITH IMPROVED SNAP ACTING OPERATING MECHANISM Nov. 22, 1966 5 Sheets-Sheet 2 Filed Sept. 4, 1964 IN VE N TO R rmy/(Badman y flzl ATTORNEY Nov. 22, 1966 BACHMAN 3,287,514

A. CIRCUIT INTERRUPTERS WITH IMPROVED SNAP ACTING OPERATING MECHANISM Filed Sept. 4, 1964 5 Sheets-Sheet 3 United States Patent 3,287,514 CIRCUIT INTERRUPTERS WITH IMPROVED SNAP ACTING OPERATING MECHANISM Anatole Bachman, Willowdale, Ontario, Canada, assignor to Federal Pacific Electric Company, a corporation of Delaware Filed Sept. 4, 1964, Ser. No. 394,474 Claims. (Cl. 200-17) This invention relates to circuit interrupters and more particularly to multipole electric switches provided with a snap-acting operating mechanism.

Circuit interrupters or switches of the class herein described are widely utilized in panelboards. In such panelboards the interrupters are grouped together for economy of space and material and convenience of operation and interconnection. Many applications require that the switches be provided with quick-make quick-break operating mechanisms. In the past the quick-make quick-break operating mechanism has included overcentering spring means and has been located alongside the contact structure and thus has added to the side-to-side size of the switch. Where large numbers of switches are used the space occupied by each switch and its associated operating mechanism becomes particularly important as reflected in the size of the finished panelboard. Therefore,

it is an object of this invention to reduce the side-to-side space requirement of circuit interrupters and it is another object of this invention to provide a more compact circuit interrupter having a quick-make quick-break operating mechanism.

It is another object of this invention to provide a compact readily assembled switch which is particularly adapted for assembly line methods of manufacture. A further object of this invention is to provide a unitized construction for circuit interrupters wherein operative portions of the interrupter may be preassembled for reducing the time and effort involved in manufacturing circuit interrupters.

In one embodiment of the invention, a circuit interrupter is provided which has a casing of insulation having its base lying in a given plane and upstanding walls defining a plurality of pole spaces. A pair of stationary contacts are mounted on the base in each of the pole spaces provided between the opposed walls thereof and a movable contact assembly for bridging the pair of stationary contacts is positioned in each of the pole spaces. The movable contact assemblies are reciprocable with respect to the base in a direction perpendicular to the plane of the base from a position in engagement with the stationary contacts to a remote open circuit position. The operating mechanism for the interrupter includes an overcentering spring means which is operable in a plane parallel to the plane of the base and which is spaced therefrom. Means are provided for interconnecting the contact assemblies and the operating mechanism for conjoint reciprocating movement of the movable contact assemblies between the engaged and remote positions.

The nature of the invention in its various aspects, and further objects and features of novelty will be better appreciated from the illustrative embodiment described below in which reference is made to the accompanying drawings. In those drawings:

FIG. 1 is a plan view, on a reduced scale, of a circuit interrupter incorporating the invention with a portion of the enclosure broken away;

FIG. 2 is a front elevational view, taken along the line 22 of FIG. 1, with some parts broken away and other parts in section showing a portion of the circuit interrupter operating mechanism;

3,287,514 Patented Nov. 22, 1966 FIG. 3 is a plan view, taken along the line 33 of I FIG. 2, of the circuit interrupter operating mechanism;

FIG. 4 is a plan view of the circuit interrupter of FIG. 1 taken along the line 44 of FIG. 5;

FIG. 5 is a side elevational view, taken along the line 5-5 of FIG. 4, showing the assembled circuit interrupter;

FIG. 6 is a front elevational view of the movable contact assembly as viewed in the direction of the arrow 6 in FIG. 5; and

FIG. 7 is an exploded side elevational view of the circuit interrupter illustrating the mode of assembly.

Referring to the drawings, and more particularly to FIG. 1 thereof, there is shown a front operated circuit interrupter 10 which may be a single pole or multipole type, the latter type being shown in the illustrative embodiment. The circuit interrupter 10 is suitably mounted in enclosure 12 having a front cover 14 which is hinged -to the enclosure at one side by hinges 16 so that the cover may be swung to open and closed positions. The cover has an opening 18 which interfits with the edge flange 20 of the interrupter cover plate 22 in the closed position of the cover 14 to exclude foreign matter from the enclosure and to prevent insertion of a tampering tool. The cover 14 is releasably latched or locked closed in a conventional manner by latch 24 which cooperates with the cover. The actuating handle 26 projects through the cover opening 18 and is of the front operated twist type. The handle is pivotally mounted on the interrupter cover plate 22 about an axis substantially perpendicular to the cover and is movable between on and off positions to operate the interrupter. The off position is shown in full lines in FIG. 1 and the on position is shown in phantom. In both the on and off positions of the handle 26 it is disposed within the area demarked by the opening 18 in the cover 14 so that the cover may be swung clear of the interrupter when unlatched without regard to the handle position.

Referring to FIG. 5, the circuit interrupter comprises a casing 28 of molded insulating material which houses and supports the elements of the interrupter mechanism. The interrupter or switch is provided at each pole with a pair of stationary contacts 30, 32 and a movable bridging contact 34. Each of the stationary contacts is secured to the bottom wall of the casing 28. The stationary contacts are provided with fiat portions 30a, 3221, respectively, which extend along the bottom wall 35 of the casing and are also provided with depending contact areas 3% and 32b, respectively, which extend at substantially right angles to the flat portions 30a, 32a. The contact areas 3% and 32]) extend into identical recesses 36 formed in the bottom wall 35. The recesses are separated from one another by a transverse wall 38 of insulation which extends upwardly from the bottom wall 35 of the casing. In the presently preferred embodiment of the invention shown in the drawings, a terminal connector 40 is shown mounted on the stationary contact 30 and afuse clip 42 is shown mounted on the stationary contact 32. When the interrupter is in its on position (FIG. 7) the circuit through the interrupter is from the terminal 40 to stationary contact 30 through the bridging contact 34 to the stationary contact 32 and thence to the fuse clip 42.

At each side of the transverse wall 38 there is provided an arc chute 44 which comprises a plurality of spaced plates 46 that are secured to 'an insulator 48 as by swaging. The are chutes 44 are maintained in operative'relation with the contact areas and are restrained from lateral movement by engagement with transverse wall 38 and projections 50 formed as part of the pole space defining walls. The metal plates 46 of the arc chutes are spaced from the stationary contacts by a portion of the insulator plate 48. Vertical movement of the arc chutes is prevented by insulating plates 60, secured to the top surfaces of the projections 50, overlying the arc chutes and in engagement with the are chute insulator 48. The are chute plates 46 and insulating plate 60 are suitably formed, adjacent the transverse wall 38, to provide clearance for the moving contact 34.

Referring to FIGS. and 6, the moving contact 34 includes a U-shaped highly conductive bridging contact member 62 of copper that is carried by a pair of insulating side plates 64. The contact member 62 has rounded contact surfaces 62a formed adjacent the free ends of the legs 66 that engage the stationary contacts 30, 32, thus providing two series breaks per pole. Contact pressure between the moving contact and the stationary contacts is built up when the moving contact is driven between the stationary contacts by the operating mechanism. In the open circuit condition the contact surfaces 62a of the moving contact are somewhat further apart than the distance between the stationary contacts. A spring mem-- ber 68, positioned between the legs 66 and reacting there against, augments the contact pressure when the switch is closed. The spring 68 has its ends 70 seated in outwardly lanced portions 72 of the legs and is thereby retained within the contact member. The contact member has two sets of laterally extending tangs 73, 74 which pass through respective ones of apertures 76 formed in the side plates 64. Each of the side plates has a pair of legs 78 adapted to straddle the transverse wall 38 and a hook-shaped portion 80 defined by an arm 82 which extends oppositely to the legs 78 and defines an opening 83 which is at right angles to the legs 78. The openings 83 in both side plates face in the same direction. One upper tang 73a on each side of the contact member 62 extends through the side plate 64 and through a guide plate 84 positioned thereby. The end of the tang 73a is headed over and secures the contact member, side plate, and guide plate together as a unitary structure. Movement of the guide plate about the tang is prevented by the rectangular tang being received in a rectangular opening in the guide plate and then being headed thereover. Each guide plate 84 has a laterally extending ear 86. The ears 86 on both sides of the assembly lie in a common plane. The purpose and function of these guide plates will be described in detail below. The upper set of apertures (FIG. 5) in the side plates 64 closely conform to their respective tangs 73 while the lower set of apertures are somewhat larger than the associated tangs 74 to allow movement of the contact member legs 66 relative to the side plates 64 when the moving contact engages the stationary contacts and is driven therebetween. In the circuit open position the lower tangs 74 are driven against the remote walls of the aperture by the inherent resilience of the contact member 62 and by the bias of spring 68 that reacts between the legs 66 thereof adjacent the tangs. When the contact surfaces 62a are in engagement with the contact surfaces 30b, 32b of the stationary contacts, the lower tangs 74 are displaced inwardly toward one another (FIG. 7).

Referring to FIGS. 4, 5 and 7, the casing 28 includes a base 35, interphase walls 52, 54 and exterior walls 56, 58. The exterior walls and the interphase Walls define between them three substantially identical pole spaces, i.e., pole A is defined by walls 52 and 56, pole B is defined by walls 52 and 54 and pole C is defined by walls.

54 and 58. Each of the walls is provided with a flat portion or support platform 88 on its upper extremity and the upper surfaces of the platforms 88 all lie in a common plane which is parallel to the plane of the base 35. The operating mechanism 90 which includes the interrupter cover plate 22 and twist handle 26 is mounted on the supports 88.

Referring to FIGS. 4 and 5 the opposed faces of pole space defining walls are provided with vertically extending grooves 92 that receive the ears 86 of the guide plates 84 and thereby constrain the movable contact member 34 for reciprocation relative to the stationary contacts in a plane perpendicular to the plane of the base. The exterior walls 56 and 58 of the casing are formed to provide a notch which is open at the top surface of the respective walls which notch is provided with a rounded bearing surface 94 at its lowermost extremity, a straight wall 96 on one side of the bearing surface, and a shorter wall 98 joined to a downwardly inclined wall 100 on the other side. The bottom of the notch provides a bearing surface 94 for the operating crank 102. The portions of the interphase walls 52 and 54 in line with the notches are cut away, as at 103, to provide a clearance for the operating crank 102.

The operating crank or common actuator 102, of insulation, is provided with hearing members 104 at each end that cooperate with the bearing surface 94 of the notches to rotatably support the actuator and to position the pivotal axis of the actuator in a plane substantially parallel to the base of the casing 28. Operating crank 102 is provided with multiple pairs of arms 106 that carry a bridging member 108. The arms 106 extend from the body 107 of the crank into each of the pole spaces A, B and C for operative engagement with respective ones of the movable contacts 34. Bridging member 108 is circular in cross section and engages the hook-shaped portion 80 of the movable contact. The members 108 provide connection between the arms 106 and the movable contacts. The various pairs of arms 106 are spaced from one another to all relative movement of the crank with respect to the interphase walls 52, 54. Coupling rod 110 is secured to the operating crank 102 and extends upwardly therefrom for engagement by a portion of the operating mechanism to be described below. Rotation of the operating crank 102 about its pivotal axis as' produced by the operating mechanism causes the reciprocation of the movable contacts 34 between the on and off positions.

The operating mechanism 90 includes the cover plate 22, that carries the twist handle 26, and a mechanism plate 112. Mechanism plate 112 is secured to the casing 28 at the supports 88 and carries a snap-acting overcentering toggle linkage 114 (FIG. 3) on its upper surface. The plate 112 lies in a plane parallel to the plane of the base 35 and the movement of the toggle 114 lies in this plane. The overcentering mechanism 114 includes a cam plate 116 pivoted at 118 on the plate 112. Overcentering spring 120 is positioned about link 122 which engages a pin 124 carried by the cam plate 116. Pin 124 forms the knee of the toggle 114. The other end of link 122 is slidable through an aperture 126 in a support member 128 which is pivotally mounted at 130 on plate 112. Spring 120 reacts between support 128 and a widened portion 122a of the link adjacent the point of engagement with the pin 124. A lever 132, pivoted at one end at 134 on the underside of the mechanism plate, is bifurcated at its free end 136 to receive the coupling rod 110 between the legs thereof. The coupling rod 110 extends upwardly through the mechanism plate 112 through aperture 138. Lever 132 is provided with a pin 140 that passes through an aperture 142 in the mechanism plate for engagement with a slot 144 formed in the cam plate 116. Pin 140 and slot 144 provide a lost-motion connection between the overcentering mechanism 114 and the coupling rod 110.

As previously described, the twist handle 26 is pivotally mounted on the cover plate 22 for movement between the on and off positions about an axis which is perpendicular to the plane of the operating mechanism 90 and the plane of the base 35 of the casing 28. Member 146 is secured to a portion of handle 26 that extends through the cover plate 22 for pivotal movement therewith at the opposite face of the plate 22 in operative relation to the overcentering mechanism 114. Member 146 has a pair of spaced legs 146a and 1461; (FIG. 3) for engagement with the toggle knee pin 124 carried by cam plate 116. In

terlocking tabs 148 and slots 150 are provided in the cover plate 22 and mechanism plate 112 respectively for securing these parts together. Positioning members 152, of insulation, are located in apertures 154 in the mechanism plate, and are retained in the plate against displacement by coaction with the cover plate and the mechanism plate. The members 152 extend below the plane defined by the supports 88 and are interposed between the exterior walls 56, 58 of the casing and the respective adjacent outside arms 106 of the operating crank 102. The insulators 152 close the notch formed in the outside walls 56 and 58 and serve to retain the bearing portions 104 of the operating crank in position in engagement with the bearing surface 94 of the notches formed in the outside walls (see FIG. 5).

The mode of assembly of the illustrative embodiment of the invention will be best understood from the following description taken in conjunction with FIG. 7. The stationary contacts 30 and 32 are secured to the base 35 of the casing 28 and then the arc chutes 44 are positioned thereover. The cover plate 60 for the arc chute is next inserted and secured to the projections 50. The moving contact assemblies '34 are then inserted into the respective pole spaces with the guide plates 86 in engagement with the grooves 92, and the legs 78 of the insulating side plates straddle the transverse wall 38. The portions of the contact on opposite sides of the wall 38 are identical and the contacts may be characterized as having their axis of symmetry aligned with one another and transverse the planes of the broad faces of the walls. The operating crank 102 is next inserted, 'being dropped into position, with the bridging members 108 entering into engagement with the hooked portions 80 of each of the movable contacts 34. The descent of the operating crank 102 continues until the bearing surfaces 104 thereon engage the bearing surfaces 94 formed in the side walls 56, 58 of the casing. Next, the mechanism plate 112 is positioned on and secured to the supports 88 with the coupling rod 110 of the operating crank 102 between the legs of the operating lever 132 carried by the mechanism plate. Insulators 152 are then inserted into the apertures 154 in the mechanism plate and are positioned between the exterior walls 56, 58 of the casing and the respective adjacent arms 106 of the operating crank 102. The cover plate 22 is then engaged wit-h the mechanism plate by means of the tabs 148 and slots 150, respectively, with the legs 146a and 146b of the handle-carried member 146 straddling the pin 124. The completed interrupter 110 is then mountable in the enclosure of FIG. 1.

The illustrative embodiment of the invention is illustrated in FIGS. 1 through 5 in the off or open circuit position. At this time the movable contacts 34 are elevated to a position clear of the stationary contacts 30, 32. When the twist handle 26 is driven from the off position to the on position, the leg 146a of the member 146 secured to the handle drives the knee pin 124 of the toggle 114 overcenter of a line between the pivots 118 and 130. During the initial portion of this movement the spring 120 is compressed between link portion 122a and support 128 thereby building up the force required to operate the interrupter. Once the center line position has been passed the pin 124 travels overcenter with a snap action which snap action is transmitted to the lever 132. The lost motion coupling between the cam plate 116 and pin 140 allows movement of the handle toward the operating position without disturbing the position of the lever 132 until the snap action is ready to occur. The snap movement of the pin 124 causes cam plate 116 to drive against the pin 140 coupled to the lever 132. When the pin 124 snaps overcenter it also drives against the leg 14612 of the member 146 and thus pivots the operating handle 26 to the on position.

When the lever 132 is driven from the off position shown in FIG. 3 to the on position, the operating crank 102 is caused to pivot on the bearing surfaces 94 provided in the exterior Walls by virtue of the connection between the coupling rod and the bifurcated lever end 136. Pivotal movement of the operating crank 102 about its axis, which is disposed in a plane perpendicular to the planes of the respective walls and interphase barrier-s, causes pivotal movement of the bridging member 108 about the crank axis. The movable contacts are restrained to vertical movement by virtue of the engagement of guide plate ears 86 thereon with the grooves 92 formed in the opposed surfaces of the walls and barriers. The snap movement of lever 132 causes a rapid movement of the contact assemblies 34 toward and into engagement with the stationary contacts 30 and 32. The rounded contact surfaces 62a of the moving contact first engage the contact surfaces 30b and 32b respectively of the stationary contacts and then are driven between them assuring firm contact pressure. The force of the spring as transmitted through the lever 132 to the common actuator or crank 102 provides sufiicient force for driving the contact surfaces 62a, 30b and 32b together against the inherent resilience of the legs 66 of the bridging member 62 and the bias of the contact pressure augmenting spring 68 positioned therebetween.

When the interrupter is to be turned reverse movement of the parts occurs, i.e., the leg 146b of the member attached to the operating handle 26 drives the pin 124 overcenter in the reverse direction. One again, the lost-motion coupling between the pin and the cam plate 116 allows movement of the handle to occur without disturbing the position of the operating crank 102. Once the pin 124 crosses overcenter then the actuator 102 is moved reversely from the position shown in FIG. 7 to the position shown in FIG. 5 and the moving contact assemblies 34 are lifted from engagement with the stationary contacts 30, 32, by virtue of the force stored in the overcentering spring 120. In the event that the interrupter is opened under load the transverse wall 38 separates the arc into two segments and the arc chutes 46 act to extinguish the arcs formed between the moving contact and the adjacent contact in a manner well known in the art.

While the overcentering mechanism 114 has been illustrated in conjunction with reciprocable contacts it may also be advantageously employed with pivoted contact arms as shown and described in my copending application entitled Circuit Interrupter, Serial No. 394,521 filed September 4, 1964 which is assigned to the assignee hereof.

While there has been disclosed above an exemplary embodiment of the invention which is presently preferred, it will be apparent to those skilled in the art that various modifications and changes may be made therein Without departing from the spirit or scope of the invention.

What I claim is:

1. A circuit interrupter including a casing having a base lying in a given plane and upstanding walls defining a plurality of pole spaces, a pair of stationary contacts mounted on said base in each of said pole spaces, movable contacts in each of said pole spaces, said movable contacts being movable in a direction perpendicular to the plane of said base from a position engaging said stationary contacts to a remote position, operating mechanism for said interrupter mounted on said casing, said operating mechanism including overcentering spring means, said overcentering spring means being operable in a plane parallel to the plane of said base, and means interconnecting said movable contacts and said operating mechanism for snap acting conjoint reciprocating movement of said movable contacts between said engaged and remote positions.

2. A circuit interrupter including a casing having a base lying in a given plane and upstanding walls defining a plurality of pole spaces, said walls having their broad faces aligned in parallel planes perpendicular to the plane of said base, a pair of stationary contacts mounted on said base in each of said pole spaces, movable contact assemblies in each of said pole spaces, said movable contact assemblies being aligned with their axis of symmetry transverse to the planes of the walls and being movable in a path perpendicular to the plane of said base from a position engaging said stationary contacts to a remote position, means for guiding said contact assemblies in said perpendicular path, operating mechanism for said interrupter mounted on said casing, said operating mechanism including overcentering spring means, said overcentering spring means being operable in a plane parallel to the plane of said base, and means interconnecting said movable contact assemblies and said operating mechanism for conjoint reciprocating movement of said contact assemblies between said engaged and remote positions along said perpendicular path.

3. A circuit interrupter including a casing having a base lying in a given plane and upstanding walls defining a plurality of pole spaces, said walls having their broad faces aligned in parallel planes perpendicular to the pane of said base, said walls formed in each pole space to provide a pair of opposed grooves perpendicular to the plane of said base, a pair of stationary contacts mounted on said base in each of said pole spaces, movable contact assemblies in each of said pole spaces, said movable contact assemblies being aligned with their axis of symmetry transverse to the planes of the walls and being movable in a path perpendicular to the plane of said base from a position engaging said stationary contacts to a remote position, said contact assemblies having portions engaging said grooves for guiding said assemblies in said perpendicular path, operating mechanism for said interrupter mounted on said casing, said operating mechanism including overcentering spring means, said overcentering spring means being operable in a plane parallel to the plane of said base, and means interconnecting said movable contact assemblies and said operating mechanism for conjoint reciprocating movement of said contact assemblies between said engaged and remote positions along said perpendicular path.

4. A multipole circuit interrupter including a casing having .a base, upstanding Walls, and interposed barriers of insulation, said walls and said interposed barriers being spaced from one another and having their broad faces aligned in parallel planes, said planes being perpendicular to the plane of the base, a pair of opposed stationary contacts mounted on said base between the confronting faces of said walls and barriers, a movable bridging contact complementary to said stationary contacts, guide means for said movable contact means formed in said opposed faces of said walls and barriers, said movable contact having portions engaging said guide means and thereby being positioned for reciprocating motion in a plane perpendicular to said base from a position in engagement with said stationary contacts and a postion remote therefrom, a common actuator bar spanning said walls and interposed barriers and having portions engaging said movable contacts in each of said spaces respectively, said actuator bar being pivoted in the walls of said device, a coupling rod secured at one end to said actuator bar, and

operating mechanism for said interrupter mounted on saidwalls opposed to said base and having an operating handle movable between a first position and a second position in a plane parallel to the plane of said base, said operating mechanism including a snap-acting overcentering mech anism connected to said handle and being operable in a parallel plane spaced therefrom, said overcentering mechanism including a lever formed to provide connection between said coupling rod and said operating mechanism said overcentering mechanism moving said movable contacts between said remote position and said engagement position in response to movement of said handle between said first position and said second position.

5. A multipole circuit interrupter including a casing open at the top and having a base and upstanding walls defining a plurality of pole spaces, said walls having their broad faces aligned in parallel planes perpendicular to the plane of the base, said walls having portions of their respective top surfaces lying in a common plane parallel to the plane of the base, stationary line and load contacts in each of said pole spaces, a bridging contact movable relative to said stationary contacts between a position in engagement therewith and a remote position, guide means in each pole space for restraining the movement of said bridging contact to a plane perpendicular to the plane of said base and parallel to the planes of said walls, the outermost of said walls of said casing being notched at their top surface to provide bearing surfaces thereon, a common actuator positioned in said notches in bearing engagement with said surfaces for pivotal movement of said actuator about an axis perpendicular to the planes of said walls, said actuator having portions having operative engagement with respective ones of said movable contacts, operating means for said interrupter mounted on the top surfaces of said Walls, said operating means including a twist handle pivotal about an axis perpendicular to the plane of the base and a snap-acting overcentering mechanism coupled to said handle and operable in a plane parallel to the plane of the base, means connecting said overcentering mechanism to said common actuator to thereby move said common actuator and said movable contacts in response to operation of said twist handle, and means carried by said operating means for retaining said common actuator in said notches.

6. Front-operated switching apparatus including an operating handle having a pivot, an overcentering spring mechanism operable in a plane perpendicular to the axis of said pivot, said overcentering spring mechanism including a link having a pivot whose axis is perpendicular to said plane and a stressed spring connected to said link and acting along a line that crosses said pivot of said link, and a lost-motion coupling between said link and said handle enabling reverse snap-acting overcentering operations of said mechanism, a switch operating crank pivoted about an axis parallel to said plane and having a pin-andslot coupling with said link for operation thereby, and companion contacts operable between closed and open positions and including one movable contact mechanically connected to said operating crank for operation thereby.

7. A multipole circuit interrupter including a casing having a base and upstanding walls defining a plurality of pole spaces, a stationary contact mounted on said base in each of said pole spaces, a movable contact in each of said pole spaces, said movable contacts being movable from a position engaging said stationary contacts to a remote position, means coupling said movable contacts for conjoint movement between the aforesaid positions, means on said walls providing bearing surfaces for pivotally supporting said coupling means, operating mechanism for said coupling means for moving said movable contacts, said operating mechanism being mounted on said walls, and means interposed between said operating mechanism and said coupling means for retaining said coupling means in engagement with said bearing surfaces.

8. A multipole circuit interrupter including a casing having a base and upstanding walls defining a plurality of pole spaces, a stationary contact mounted on said base in each of said pole spaces, a movable contact member in each of said pole spaces, said movable contact members being movable from a position engaging said stationary contacts to a remote position, a crank having axially aligned bearing portions and axially aligned eccentric portions for coupling said movable contact members for conjoined movement between the aforesaid positions, notches having upwardly facing openings formed in said walls providing bearing surfaces at the bottom of said notches engaged by the bearing portions of said crank for pivotally supporting said crank, operating mechanism for said crank for moving said movable contact members, said operating mechanism being mounted on said walls,

and means interposed between said operating mechanism and said bearing portions of said crank for retaining said bearing portions in engagement with said bearing surfaces.

9. A multipole circuit interrupter including a casing having a base and upstanding walls defining a plurality of pole spaces, a stationary contact mounted on said base in each of said pole spaces, a movable contact member in each of said pole spaces, said movable contact members being movable from a position engaging said stationary contacts to a remote position, a crank having axially aligned bearing portions and axially aligned eccentric portions for coupling said movable contact members for conjoined movement between the aforesaid positions, notches having upwardly facing openings formed in said walls pro viding bearing surfaces at the bottom of said notches engaged by the bearing portions of said crank for pivotally supporting said crank, said crank eccentric portions engaging said movable contact members in a direction transverse the path of movement of said movable contact members when said crank is positioned in said notches, operating mechanism for said crank for moving said movable contact members, said operating mechanism being mounted on said walls, and means interposed between said operating mechanism and said bearing portions of said crank for retaining said bearing portions in engagement with said bearing surfaces.

10. A multipole circuit interrupter including a casing having a base and upstanding walls defining a plurality of pole spaces, a stationary contact mounted on said base in each of said pole spaces, a movable contact members in each of said pole spaces, said movable contact members being movable from a position engaging said stationary contacts to a remote position, a crank having axially aligned bearing portions and axially aligned eccentric portions for coupling said movable contact members for conjoined movement between the aforesaid positions, notches having upwardly facing openings formed in said walls providing bearing surfaces at the bottom of said notches engaged by the bearing portions of said crank for pivotally supporting said crank, a front cover part secured to said casing, a pivoted manual actuator mounted in said cover for motion about an axis perpendicular thereto, said manual actuator having a portion engageable with said crank, and a part confined between said front plate and the bearing portions of said crank opposite the bottoms of said notches.

References Cited by the Examiner UNITED STATES PATENTS 3,087,039 4/1963 Bachman 200 l66 3,097,275 7/1963 Wiktor ZOO-78 3,212,346 10/1965 Bachman 74100 ROBERT K. SCHAEFER, Primary Examiner.

I. R. SCOTT, Assistant Examiner. 

1. A CIRCUIT INTERRUPTER INCLUDING A CASING HAVING A BASE LYING IN A GIVEN PLANE AND UNPSTANDING WALLS DEFINING A PLURALITY OF POLE SPACES, A PAIR OF STATIONARY CONTACTS MOUNTED ON SAID BASE IN EACH OF SAID POLE SPACES, MOVABLE CONTACTS IN EACH OF SAID POLE SPACES, SAID MOVABLE CONTACTS BEING MOVABLE IN A DIRECTION PERPENDICULAR TO THE PLANE OF SAID BASE FROM A POSITION ENGAGING SAID STATIONARY CONTACTS TO A REMOTE POSITION, OPERATING MECHANISM FOR SAID INTERRUPTER MOUNTED ON SAID CASING, SAID OPERATING MECHANISM INCLUDING OVERCENTERING SPRING MEANS, SAID OVERCENTERING SPRING MEANS BEING OPERABLE IN A PLANE PARALLEL TO THE PLANE OF SAID BASE, AND MEANS INTERCONNECTING SAID MOVABLE CONTACTS AND SAID OPERATING MECHANISM FORT SNAP ACTING CONJOINT RECIPROCATING MOVEMENT OF SAID MOVABLE CONTACTS BETWEEN SAID ENGAGED AND REMOTE POSITIONS. 